In German Offenlegungsschrift No. 2606545, there is disclosed a changeover device which includes means for removing and/or installing the roller shell and a centering device which centers the roller journal during the changeover operation. This centering device includes a conical head portion which engages in a conically shaped recess.
In such an arrangement, the changeover device is moved, by means of a crane, along the end face of the roller which is provided with the shell or casing to be replaced. Thereafter, a tubular extension portion, which is provided with a disc member which closes one end face thereof and against which a conically-shaped component is retained by means of an electromagnet, is moved into a corresponding conical-shaped recess. A screw-threaded spindle is then screwed into a threaded bore formed in the roller shell casing to be interchanged, and the screw-threaded spindle is connected to a means for entraining the piston of a hydraulic piston and cylinder arrangement.
By actuating the hydraulic piston and cylinder arrangement, the shell or casing is removed from the roller core and subsequently replaced by another casing by reversing the above-described sequence of steps.
Such a known device permits small, lightweight roller shells or casings to be interchanged. However, it is extremely difficult to remove the bearing body for the roller prior to the removal of the roller shell or casing over the roller bearing remaining on the roller journal. This is particularly true in large calenders which have large and heavy bearing bodies. This is because extensive damage is caused even by slight tilting of the bearing arrangements.
Profile manufacturers in, for example, the tyre-manufacturing industry, demand that the profiled roller shell or casing must be interchangeable within the space of a few minutes. It is particularly important that no tilting forces whatsoever should act on the bearing body during the changeover operation because the component parts thereof would almost certainly be damaged and need to be replaced. This, in turn, would cause the changeover process to be considerably extended, with the result that the calendering plant will be idle for a length period of time.